// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Slightly adapted for inclusion in V8.
// Copyright 2016 the V8 project authors. All rights reserved.

#ifndef V8_BASE_DEBUG_STACK_TRACE_H_
#define V8_BASE_DEBUG_STACK_TRACE_H_

#include <stddef.h>

#include <iosfwd>
#include <string>

#include "src/base/base-export.h"
#include "src/base/build_config.h"

#if V8_OS_POSIX
#include <unistd.h>
#endif

#if V8_OS_WIN
struct _EXCEPTION_POINTERS;
struct _CONTEXT;
#endif

namespace v8 {
namespace base {
    namespace debug {

        // Enables stack dump to console output on exception and signals.
        // When enabled, the process will quit immediately. This is meant to be used in
        // tests only!
        V8_BASE_EXPORT bool EnableInProcessStackDumping();
        V8_BASE_EXPORT void DisableSignalStackDump();

        // A stacktrace can be helpful in debugging. For example, you can include a
        // stacktrace member in a object (probably around #ifndef NDEBUG) so that you
        // can later see where the given object was created from.
        class V8_BASE_EXPORT StackTrace {
        public:
            // Creates a stacktrace from the current location.
            StackTrace();

            // Creates a stacktrace from an existing array of instruction
            // pointers (such as returned by Addresses()).  |count| will be
            // trimmed to |kMaxTraces|.
            StackTrace(const void* const* trace, size_t count);

#if V8_OS_WIN
            // Creates a stacktrace for an exception.
            // Note: this function will throw an import not found (StackWalk64) exception
            // on system without dbghelp 5.1.
            explicit StackTrace(_EXCEPTION_POINTERS* exception_pointers);
            explicit StackTrace(const _CONTEXT* context);
#endif

            // Copying and assignment are allowed with the default functions.

            ~StackTrace();

            // Gets an array of instruction pointer values. |*count| will be set to the
            // number of elements in the returned array.
            const void* const* Addresses(size_t* count) const;

            // Prints the stack trace to stderr.
            void Print() const;

            // Resolves backtrace to symbols and write to stream.
            void OutputToStream(std::ostream* os) const;

            // Resolves backtrace to symbols and returns as string.
            std::string ToString() const;

        private:
#if V8_OS_WIN
            void InitTrace(const _CONTEXT* context_record);
#endif

            // From http://msdn.microsoft.com/en-us/library/bb204633.aspx,
            // the sum of FramesToSkip and FramesToCapture must be less than 63,
            // so set it to 62. Even if on POSIX it could be a larger value, it usually
            // doesn't give much more information.
            static const int kMaxTraces = 62;

            void* trace_[kMaxTraces];

            // The number of valid frames in |trace_|.
            size_t count_;
        };

    } // namespace debug
} // namespace base
} // namespace v8

#endif // V8_BASE_DEBUG_STACK_TRACE_H_
